This invention relates generally to the control of electrical power distribution, and more particularly limiting overheating due to supply voltage reduction, the invention having particular application to electrical equipment associated with operation of pools or spas.
U.S. Pat. No. 5,133,818 discloses operation of a water pump for circulating water to and from a spa or hot tub, the pump driven by an electrical motor from which heat is transferred to the circulating water stream. If the supply voltage to the motor and/or heater appliance drops, electrical current supplied to the motor and/or heater appliance can increase significantly, resulting in risk of electrical overheating and risk of damage to electrical circuitry or components. There is a need for method and means to alleviate these problems, as well as in other applications or systems. There is also need for means to control electrical power delivery to the pump motor and/or heater appliance, as a function of changes in motor and/or heater appliance supply voltage level.